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  <h1>Source code for django.db.models.functions.window</h1><div class="highlight"><pre>
<span></span><span class="kn">from</span> <span class="nn">django.db.models.expressions</span> <span class="k">import</span> <span class="n">Func</span>
<span class="kn">from</span> <span class="nn">django.db.models.fields</span> <span class="k">import</span> <span class="n">FloatField</span><span class="p">,</span> <span class="n">IntegerField</span>

<span class="n">__all__</span> <span class="o">=</span> <span class="p">[</span>
    <span class="s1">&#39;CumeDist&#39;</span><span class="p">,</span> <span class="s1">&#39;DenseRank&#39;</span><span class="p">,</span> <span class="s1">&#39;FirstValue&#39;</span><span class="p">,</span> <span class="s1">&#39;Lag&#39;</span><span class="p">,</span> <span class="s1">&#39;LastValue&#39;</span><span class="p">,</span> <span class="s1">&#39;Lead&#39;</span><span class="p">,</span>
    <span class="s1">&#39;NthValue&#39;</span><span class="p">,</span> <span class="s1">&#39;Ntile&#39;</span><span class="p">,</span> <span class="s1">&#39;PercentRank&#39;</span><span class="p">,</span> <span class="s1">&#39;Rank&#39;</span><span class="p">,</span> <span class="s1">&#39;RowNumber&#39;</span><span class="p">,</span>
<span class="p">]</span>


<div class="viewcode-block" id="CumeDist"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.CumeDist">[docs]</a><span class="k">class</span> <span class="nc">CumeDist</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;CUME_DIST&#39;</span>
    <span class="n">output_field</span> <span class="o">=</span> <span class="n">FloatField</span><span class="p">()</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span></div>


<div class="viewcode-block" id="DenseRank"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.DenseRank">[docs]</a><span class="k">class</span> <span class="nc">DenseRank</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;DENSE_RANK&#39;</span>
    <span class="n">output_field</span> <span class="o">=</span> <span class="n">IntegerField</span><span class="p">()</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span></div>


<div class="viewcode-block" id="FirstValue"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.FirstValue">[docs]</a><span class="k">class</span> <span class="nc">FirstValue</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">arity</span> <span class="o">=</span> <span class="mi">1</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;FIRST_VALUE&#39;</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span></div>


<span class="k">class</span> <span class="nc">LagLeadFunction</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span>

    <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">expression</span><span class="p">,</span> <span class="n">offset</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">default</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="o">**</span><span class="n">extra</span><span class="p">):</span>
        <span class="k">if</span> <span class="n">expression</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
            <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span>
                <span class="s1">&#39;</span><span class="si">%s</span><span class="s1"> requires a non-null source expression.&#39;</span> <span class="o">%</span>
                <span class="bp">self</span><span class="o">.</span><span class="vm">__class__</span><span class="o">.</span><span class="vm">__name__</span>
            <span class="p">)</span>
        <span class="k">if</span> <span class="n">offset</span> <span class="ow">is</span> <span class="kc">None</span> <span class="ow">or</span> <span class="n">offset</span> <span class="o">&lt;=</span> <span class="mi">0</span><span class="p">:</span>
            <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span>
                <span class="s1">&#39;</span><span class="si">%s</span><span class="s1"> requires a positive integer for the offset.&#39;</span> <span class="o">%</span>
                <span class="bp">self</span><span class="o">.</span><span class="vm">__class__</span><span class="o">.</span><span class="vm">__name__</span>
            <span class="p">)</span>
        <span class="n">args</span> <span class="o">=</span> <span class="p">(</span><span class="n">expression</span><span class="p">,</span> <span class="n">offset</span><span class="p">)</span>
        <span class="k">if</span> <span class="n">default</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
            <span class="n">args</span> <span class="o">+=</span> <span class="p">(</span><span class="n">default</span><span class="p">,)</span>
        <span class="nb">super</span><span class="p">()</span><span class="o">.</span><span class="fm">__init__</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">extra</span><span class="p">)</span>

    <span class="k">def</span> <span class="nf">_resolve_output_field</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
        <span class="n">sources</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_source_expressions</span><span class="p">()</span>
        <span class="k">return</span> <span class="n">sources</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">output_field</span>


<div class="viewcode-block" id="Lag"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.Lag">[docs]</a><span class="k">class</span> <span class="nc">Lag</span><span class="p">(</span><span class="n">LagLeadFunction</span><span class="p">):</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;LAG&#39;</span></div>


<div class="viewcode-block" id="LastValue"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.LastValue">[docs]</a><span class="k">class</span> <span class="nc">LastValue</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">arity</span> <span class="o">=</span> <span class="mi">1</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;LAST_VALUE&#39;</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span></div>


<div class="viewcode-block" id="Lead"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.Lead">[docs]</a><span class="k">class</span> <span class="nc">Lead</span><span class="p">(</span><span class="n">LagLeadFunction</span><span class="p">):</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;LEAD&#39;</span></div>


<div class="viewcode-block" id="NthValue"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.NthValue">[docs]</a><span class="k">class</span> <span class="nc">NthValue</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;NTH_VALUE&#39;</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span>

    <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">expression</span><span class="p">,</span> <span class="n">nth</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="o">**</span><span class="n">extra</span><span class="p">):</span>
        <span class="k">if</span> <span class="n">expression</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
            <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s1">&#39;</span><span class="si">%s</span><span class="s1"> requires a non-null source expression.&#39;</span> <span class="o">%</span> <span class="bp">self</span><span class="o">.</span><span class="vm">__class__</span><span class="o">.</span><span class="vm">__name__</span><span class="p">)</span>
        <span class="k">if</span> <span class="n">nth</span> <span class="ow">is</span> <span class="kc">None</span> <span class="ow">or</span> <span class="n">nth</span> <span class="o">&lt;=</span> <span class="mi">0</span><span class="p">:</span>
            <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s1">&#39;</span><span class="si">%s</span><span class="s1"> requires a positive integer as for nth.&#39;</span> <span class="o">%</span> <span class="bp">self</span><span class="o">.</span><span class="vm">__class__</span><span class="o">.</span><span class="vm">__name__</span><span class="p">)</span>
        <span class="nb">super</span><span class="p">()</span><span class="o">.</span><span class="fm">__init__</span><span class="p">(</span><span class="n">expression</span><span class="p">,</span> <span class="n">nth</span><span class="p">,</span> <span class="o">**</span><span class="n">extra</span><span class="p">)</span>

    <span class="k">def</span> <span class="nf">_resolve_output_field</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
        <span class="n">sources</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_source_expressions</span><span class="p">()</span>
        <span class="k">return</span> <span class="n">sources</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="o">.</span><span class="n">output_field</span></div>


<div class="viewcode-block" id="Ntile"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.Ntile">[docs]</a><span class="k">class</span> <span class="nc">Ntile</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;NTILE&#39;</span>
    <span class="n">output_field</span> <span class="o">=</span> <span class="n">IntegerField</span><span class="p">()</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span>

    <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">num_buckets</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="o">**</span><span class="n">extra</span><span class="p">):</span>
        <span class="k">if</span> <span class="n">num_buckets</span> <span class="o">&lt;=</span> <span class="mi">0</span><span class="p">:</span>
            <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s1">&#39;num_buckets must be greater than 0.&#39;</span><span class="p">)</span>
        <span class="nb">super</span><span class="p">()</span><span class="o">.</span><span class="fm">__init__</span><span class="p">(</span><span class="n">num_buckets</span><span class="p">,</span> <span class="o">**</span><span class="n">extra</span><span class="p">)</span></div>


<div class="viewcode-block" id="PercentRank"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.PercentRank">[docs]</a><span class="k">class</span> <span class="nc">PercentRank</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;PERCENT_RANK&#39;</span>
    <span class="n">output_field</span> <span class="o">=</span> <span class="n">FloatField</span><span class="p">()</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span></div>


<div class="viewcode-block" id="Rank"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.Rank">[docs]</a><span class="k">class</span> <span class="nc">Rank</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;RANK&#39;</span>
    <span class="n">output_field</span> <span class="o">=</span> <span class="n">IntegerField</span><span class="p">()</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span></div>


<div class="viewcode-block" id="RowNumber"><a class="viewcode-back" href="../../../../../ref/models/database-functions.html#django.db.models.functions.RowNumber">[docs]</a><span class="k">class</span> <span class="nc">RowNumber</span><span class="p">(</span><span class="n">Func</span><span class="p">):</span>
    <span class="n">function</span> <span class="o">=</span> <span class="s1">&#39;ROW_NUMBER&#39;</span>
    <span class="n">output_field</span> <span class="o">=</span> <span class="n">IntegerField</span><span class="p">()</span>
    <span class="n">window_compatible</span> <span class="o">=</span> <span class="kc">True</span></div>
</pre></div>

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